Smoke-preventer



B. L. AMES.

, SMOKE PREVENTER.

APPLICATION FILED SEPT- I, 1918.

1,397, 1 55, Patented Nov. 15, 1921.

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T0 THANKFUL ir. Aliens,

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AppIication filed September The invention relates to an improvement in smoke preventers and is especially intended for employment in connection with coal fed boiler furnaces to introduce a supply.

of air mingled with steam over the surface of the fire for a. limited period after firing for the purpose of preventing the formation of smoke and excess gas. Where an apparatus of this sort is employed it is desirable to open a passage for the air and steam feed as soon as the feed door of the furnace is opened and to continue the injection for a limited time after the furnace feed door is closed. In apparatus hitherto invented by me there has been employed means for automatically rendering operative the smoke preventer by turningon the air and feed supply by opening the feed door of the furnace, and for rendering inoperative or shutting off the smoke preventer medium after a period of activity, (see for instance Patent No. 1,166,880 granted to me January 4, 1916).

The object of the present invention is to provide an improvement in the automatic means for rendering operative and inoperative or turning on and shutting off the smoke preventer medium.

The invention will be fully understood from the following description when taken in connection with the accompanying drawings and the novel features thereof will be pointed out and clearly defined in the claims at the close of this specification.

In the drawings, Figure 1 is an elevation partly broken away showing a boiler furnace front provided with a smoke preventer embodying the invention.

F 1g. 2 1s an enlarged sectional view on line 2-2 of Fig. 1 to show in detail'the air and steam injector.

Fig. 3 is an enlarged sectional view in detail showing the valveand' cylinder mecha nism for controlling the feed and the shut off of the air and steam to the conduit which discharges them into the furnace.

Specification of Letters Patent.

' Patented Nov. 15,1921.

11, 191s. Serial no. 253,623.

Fig. 4 is a detail view of the upper whistle valve and cam for operating the same which is opened by closing the furnace feed door and controls the starting of the automatic shut ofl device for the smoke preventer.

Fig. 5is a detail view of the lower whistle valve and actuating cam which is actuated by the opening "of the fire door to open the connection for rendering thesmoke preventer operative. 1*

Referring now to the drawings, 1 is the front plate of a boiler furnace provided with fuel feed doors 2, 2. Said doors are of hinged type and by means of suitable intermediate connecting mechanism actuate the horizontal slide rod 3 so that the opening of either of the doors 2 will slide the red to the right as shown in Fig. 1 andwhen either door is closed if only one door is'open or when the last door is closed it both doors are open the spring '79 will actuate said slide tervals a series of air ducts 8 extending toward the interior of the furnace. A nozzle 9 extends from each branch pipe 6 into one of the air ducts 8. Steam passing from the pipe 4: through the branches 5 and extensions 6 is discharged through the nozzles 9 and mirgles with the air in the duct 8 and thence is discharged into the furnace. In the form of construction shown in the drawings the steam pipe at which carries the several branch pipes 5 is connected by a short vertical pipe 10 and couplings with the steam pipe 11 which also extends along the front side of the furnace front plate 1. Said steam pipe 11 is connected with the upper vcl'ianiher of a. vertical steam cylinder 12 which is divided by a partition 15 into two chambers. A. steam pipe- 13 which is con nected with the steam pipe 1d leading from the boiler opens into the lower chamber of cylinder12. the boiler not being shown. T he cylinder 12 is formed with a partition 15. Said partition 15 is formed with an orifice through which steam from the pipe 13 which enters the lower end of the cylinder may at certain times pass to the pipe 11. A valve 16, however, is normally seated to close said orifice and prevent passage of steam into the pipe 11.

' The valve 16 is provided with a stem 17 and is normally kept seated against the pressure of the steam coming into the cylinder through the pipe 13 by means of an arm 18 pivoted. at 19 which bears against the upper end of the valve stem 17 and'which is held down by the pressure of a spring 20 as will be more particularly described, the

stress of the spring 20 being suflicient to overcome the opening pressure of the steam. As long as the valve 16 is seated steam cannot pass into the pipe 11 and therefore cannot be injected through the branches 5 and nozzles 9 into the furnace.

The air to the conduit 7 is supplied through a box 21 located in front 01 and attached to the front plate of the furnace. The said. air box is provided with a cover 22 which is normally closed and which is opened by means of steam pressure introduced into the box through the pipe 23 connected with the pipe 11 and supplied therefrom. WVhen, however, the valve 16 is closed, thereby shutting off the steam from the pipe 11 the steam will also be shut off from the pipe 23 so that the cover 22 will remain closed. The detail mechanism within the box 21 whereby the steam introduced through thepipe 23 actuates the cover 22 is not claimed as a part oi this invention and therefore, is not shown in detail, but briefly, there is, connected with the underside of the cover 22 a pipe 24 into which loosely fits a branch 25 from the pipe 23, said pipe 24 being vertically slidable on the pipe 25. The steam passing up through the pipe 25 discharges into the pipe 24 and presses on the underside of the cover 22 to lift it. When the pressure is released, the cover'22 will fall back onto its seat and prevent admission of the outside air. There is an opening from the air boX 21 through the front plate 1 01" the "furnace into the conduit 7 so that the air which enters the air box 21 will pass into the conduit 7.

The means for controlling the opening and closing of the valve 16 and for controlling the duration of the period during which said valve will remain open. and the air and steam injector will be active, will now be described.

Two cylinders 27 and 28 are placed one above the other in any convenient location and suitably mounted at opposite ends 01 a frame mount 26. A piston-29 operates within the upper cylinder 27 and a piston 30 op- Ierates within. the lower cylinder 28; These pistons are secured on opposite ends of a piston rod 31. which. passes through the lower head 32 of the upper cylinder 27 and through theupper head 33 of'thelower cylinder so that the'two pistons iwill always move in unison. The length of the piston rod issuch that when he lower piston 30 is seated at the lower end of the lower cylinder 28 the piston 29 will be elevated somewhat above the lower head 32 of the upper cylinder 27, so that when the piston 29 is at its lowermost position there will still be a space 34 below the piston 29. The upper portion of thepiston rod 31 is of reduced diameter, the smaller diameter extending not only for that portion which passes through the piston 29 but also for some distance below it, forming a shoulder 35 on which is normally seated a float check valve 36 which is capable of sliding movement on the reduced portion 37 of the piston rod.

The piston 29 is formed with a plurality of vertical apertures 33 passing through it. small by-pass 39 leads from the upper end of the cylinder 27 around outside of the piston and opens into the space 34 on the underside 01' the piston in the cylinder 27. The port 40 which forms a part of the by-pass 39 where it opens into the upper end of the cylinder is controlled by needle valve 41 which may be adjusted so as to regulate or vary the size of the passage atthat point.

The upper cylinder 27 should be filled or nearly filled with oil or some other suitable downwardly turned portion 431 formed inv sections coupled together and terminating in an exhaust portion 432. The downwardly turned portion 431 has a branch connection 421 connecting with the pipe 42 at some point intermediate between the connection of the pipe 431 with the pipe 43 and its connection with the exhaust pipe 432. A valve A is inserted in the pipe 431 between the pipe 43 and the connection of the branch pipe 421. Said valve controls the admission of steam from the boiler through pipe 14 and branch 43 to the pipe 42 which leads into the lower end of the cylinder 28. Thus the valve A controls the admission of boiler pressure into the lower end of the cylinder 28 below the piston 30.

A. valve B is inserted in pipe 431 between its connection with the branch 421 and the exhaust pipe 432. This valve controls the discharge of the steam from the cylinder 28 back through the pipe 42 and branches 421 and 431 to the exhaust pipe 432;

Said valves A and B are so constructed and controlled that when one of them is open the other will always be closed as will be hereinafter described' 1 Any suitableformof valve A and B may be employed to control the inlet and exhaust is a globe whistle valve and is provided with.

a casing 44; having a partition 45 within which is an aperture for the passage of-the steam, said aperture being surrounded by a seat on which is adapted to be seated the valve head 46 to close saidaperture. A spring 47 coiled around the valve stem 48 tends to keep the said valve closed. The said valve is provided with a skeleton guide portion 49 on the opposite side of the valve head 46 from the stem @8. Said guide portion 49 extends through the port or orifice in the partition 45 and is engaged by one end of a pin 50 which is longitudinally slidable in a guide hole in the side of the valve casing. The outer end of said pin is engaged by one arm of a lever 51 fulcrumed at 52 to a fixed part of the frame work, the other arm of said lever being adapted to be engaged by a cam 53 which is mounted on a vertical rod or shaft 54. Said vertical rod or shaft 54: is journaled at its ends in suitable bearings and is adapted to be rocked on its axis as will be hereinafter described.

The valve B is similar to the valve A having a partition 55 within which is an aperture closed by a valve head 56 and having a stem 58 around which is coiled a spring 57. lit is provided with a guide portion 59 the end of which is engaged by a pin 60 slidable in a guide hole in the sideof the casing. The outer end of said pin is engaged by one arm of the lever 61 fulcrumed at 62 the other arm of said lever being engagedby a cam 63 mounted on said shaft 54:. Said cams 53 and 63 are so shaped and adjusted on said shaft that the said levers 51 and 61 will be engaged by said cams 53 and 63 respectively at such relative times that as soon as one of the valves is opened the other valve will be closed. When the valve A is open boiler pressure will pass through the pipe 42 into the lower end of the cylinder 28 and the passage to the exhaust will be closed by the valve B. as soon as the valve A is closed to cut off boil r pressure from the cylinder 28 the valve 13 will be opened and the steam from the cylinder 28 will exhaust through the pipe 432. When the feed doors are both closed the valve A is closed and the valve 13 is open. When one or both of the feed doors is open the valve A is open and the valve B is closed.

The rod 74 is provided with a pinion 65 which engages with the rack 66 mounted on the horizontal slide rod 3. Said slide rod is connected by suitable mechanism with the hinged fire doors 2, 2 in such manner that whenever either one or both of said fire doors 2, 2 is opened the slide rod 3 will move to the right and rotate the'vertical rod 54 in a a direction clock-wise to open the upper valve A and close the lower valve B and the closing of the door, if only one door has been open, and the closing of both doors if both doors have been open will rotate the shaft or rod 54 in the reverse direction and open the lower valve and close the upper valve. One means by which the opening of the fire doors 2, 2 will actuate the slide rod 3 to the right is shown and described in Patent No. 1,166,880 granted tome, Jan. at, 1916.

Briefly described each door 2 is provided with hinged members 68 which cooperate with hinged members 69 secured to the front plate 1 of the furnace, said members being pivotally secured together by means of a vertical rod 70 which is fast to the hinge member of the door and turns with it. The rods 70 are each provided on the upper end with a sprocket 71 which is connected with a sprocket 72 by means of a chain 73. The sprocket 72 is loosely mounted on the lower end of a shaft 7a mounted in bearings 75 secured to the front plate 1. Fast on each shaft 7 1 is a collar 7 6 carrying a projection 77vwhich engages one side ofa projection 78 secured to the sprocket 72. The relation of the collar 76 to the sprocket 72 is such that the projection 78 on the sprocket engages the projection 7 7 on the collar 7 6 wh n the door 2 is closed. Therefore while a door is being opened the lug 78 on the sprocket 72 engages the. lug 77 on thecollar and rotates the shaft- 74 thereby actuating the rod to move to the right and rotate the vertical rod 5% to open the valve A and close valve B. While the door is being closed the loosely mounted sprocket 72 turns back to its former position on the shaft.

The doors 2, 2 open in opposite directions to each other. Each shaft 74: is provided on its upper end with a pinion 65 which engages a rack 66secured to the horizontal slide rod 3. The racks 66 and slide rod 3 are slidably mounted in bearings. One of the pinions, the left hand pinion 65 as shown in the drawings, is so mounted as to engage with the front side of the rack which is toothed on its front face while the right hand pinion 65 is so mounted as to engage with its rack 66 on the side toward the fur nace front plate, said rack being toothed on the side toward the furnace.

A spring 7 9 is coiled around the slide rod 3, one end of said spring abutting against a bearing 80 which is fixed to the front plate of the furnace and the other end of said spring abutting against a collar 81 fasten the slide rod. This spring is putunder tension when the slide rod moves to the right when the fire doors are opened and moves the slide rod back when the fire doors are closed.

While I have shown and described one means by which the opening of a fire door will. rotate the shaft 5 1 in one direction and the closing of a door controls mechanism to rotate the said shaft in the reverse direction, any other suitable meansfor accomplishing this result may be employed, the essential feature so far as the present invention is concerned being that the rocking of the shaft in the two directions should be controlledframe 26 which also forms the lower head of the upper cylinder 27, and the lower end of said spring 20 abuts against a collar 82 made fast to the rod 31. Said collar bears against the upper side of the arm 18. The said arm passes through a slot 84 in one of the sides of the frame 26, said slot 84 being of sufficient height to permit a limited up and down rocking movement of the arm 18 but limiting the extent of its upward movement. The rod 31 is capable ofa greater range of movement vertically than the arm 18.

l/Vhen either one of the fire doors 2. 2 is opened thereby opening the valve A .and closing the valve l3. steam fromthe boiler through pipes 14 and 43 passes through the pipe 42 into the lower end of the cylinder 28 thereby lifting the piston 30 and the rod' 31. This carries up the collar 82, compress ing the spring'2-O and relieving the downward pressure on the arm 18. Boiler pres sure from the pipe 14 continually passes through the pipe 13 into the lower end of cylinder 12 and tends to unseat the valve 16 but the lifting action of the steam is nor mally resisted by the stop effect of the spring pressed arm 18. As soon as the downward pressure on the arm 18 however has been relieved by the upward movement of the piston 30 and rod 31, the valve 16 will be free to respond to the lifting action of the steam through the pipe 13 and the steam will pass through the aperture in the partition 15 into the upper chamber of the cylinder 12 thence through the pipe 11 and thence through the connecting pipes 10 and 4 and become operative to discharge through the nozzles 9 into the interior of the furnace. At the same time also steam will pass from the pipe 11 through the pipe 23 into the air box 21. lifting the cover 22 and permitting the inflow of air from the outside into the conduit 7 and thence through the duct 8 to be mingled with the steam from the noz- Zles 9 and discharged into the furnace.-

The pressure of the steam in the pipe 42 will carry the piston rod 31 far enough up to move the upper piston 29 to the upper end of its stroke. In doing this the oil or other fluid within the cylinder 27 on the upper side of the piston will flow down through the apertures 38 into the lower part of the cylinder. The float check valve 36 which rests on the shoulder 35 of the piston rod will becarried up with the piston 29. The pressure of the steam through the pipe 42 will keep the pistons 30 and 29 at the upper end of their stroke as long as the valve A remains open, which will be as long as the doors remain open, without requiring any attention by the fireman. Moreover the cams 53 and 63 are so shaped and adjusted on the shaft 54 that the valve A will be opened the valve B will be closed at the very beginning of the opening movement of either one of the fire doors so that the steam will be'admitted through the pipe 42 to lift the piston 30 and thereby permit the valve 16 to be lifted and render the smoke preventer operative almost instantly at the beginning of the opening of the fire door.

When the fire door is closed, if only one of them has been opened, or when the last one is closed if more than one has been opened. the valve A will be closed and the valve B will be opened allowing the steam within the pipe 42 to exhaust through the pipe 431 and exhaust 432. The piston rod 31 and the connected pistons 29 and 30 are now permitted to descend, the descent being aided by the stress of the spring 20 but the steam through the pipe 13 will continue to hold the valve 16 raised from its seat and keep the smoke preventer operative through the nozzles 9 and ducts 8 until the valve 16 becomes seated. The seating of the valve 16 will not take place until the piston rod 31 has descendedpractically to the bottom of its stroke, that is, far enough for the collar 82 on the rod 31 to press the lever arm 18 down to cause the valve 16 to become seated.

As soon as the piston 29 begins to descend under the pull of the spring 20 the float check valve 36 will float upward from its seat on the shoulder 35 and close the lower ends of the apertures 38 and the downward pressure of the piston will force the oil or other fluid which is now on the under side of the piston through the by pass 39 and past the needle valve 41 into the upper part of the cylinder 27 on the upper side of the piston 29. The piston 29 however can not descend any faster than is permitted by the discharge of the fluid through the by .ass 39 from the under side of the piston. The needle valve may be so adiusted as to regulate the speed of flow of the liquid through the by pass. The steam from the pipe 13 past valve 1.6 and through the pipe 11 to render the smoke preventer operative will continue until the piston29 has completed its descent. Thus the smoke preventer will continue operative for some period of time after the fire doors are closed and as above described this period of time may be regulated as desired by means of the needle valve 41.

lVhat 1. claim is:

1. ln a smoke preventer for a boiler furhaving a fire door, a steam pipe, and connections for supplying a blast of steam into the furnace, said connections including a cylinder with an inlet and an outlet pipe.

for the steam, a valve within said cylinder which controls the passage of steam from said cylinder to, the furnace, and having a stem which projects through the head of the cylinder, a second cylinder havin a passage therein, a rod connected with said piston which projects out through the head of the cylinder, a movable detent connected with said rod which engages the stem of said fi st valve, a spring which acts upon said detent to normally hold said first valve from being opened by the steam pressure in its cylinder, a steam inlet pipe connected with said-second cylinder whereby steam is admitted to move said piston and rod in a direction to release said detent against the pressure of the spring,,a valve which controls the admission of steam to said piston cylinder, and means whereby the opening of the furnace fire door will cause said last mentioned valve to be opened and admit steam to release said detent to render the steam blast operative.

2, In a smoke preventer for a boiler fur nace having a fire door, a steam supply pipe, a branch pipe leading therefrom, and connections forinjecting a blast of steam into the furnace, an exhaust pipe connected with said branch pipe, a rocker shaft, means whereby the opening of the fire door will cause the shaft to rotate in one direction, means controlled by the closing of the fire door to cause the said shaft to rock in the reverse direction, a valve which controls the opening and closing of the supply of steam to said branch injector pipe, a detent for normally holding said valve closed, steam actuated means for releasing;- said detent, a valve which controls the admission of steam to release said detent, a valve which controls the passage from said branch pipe to the exhaust pipe, two cams mounted on said rocker shaft, means actuated by one of said cams whereby the rotation of said shaft when the door opens will cause the detent controlling; valve to open and permit the detent to be released, the blast controlling valve then being opened by the steam pressure, and means actuated by the other cam, whereby the rotation of the same shaft when the door is closed will cause the exhaust valve to open.

3. In a smoke preventer for a boiler furnace having a fire door, a steam supply pipe, a branch pipe leading therefrom, and connections for injecting a blast of steam into the furnace, an exhaust pipe connectedwith said branch pipe, a rocker shaft, means whereby the opening of thefire door will cause the shaft to rotate in one direction, means COl'lbl'OllECl by thevclosing of the fire door to cause said shaft to rock in the reverse direction, a valve which controls the opening and closing of the supply of steam to said branch injector pipe, a detent for normally holding said valve closed, steam actuated means; for releasing said detent, a valve which controls the admission of steam to release said detent, a valve which controls the passage from said branch pipe to the exhaust pipe, two cams mounted on said rocker shaft, means actuated by one of said cams whereby the rotation of said shaft when the door opens will cause the detent controlling valve to open and permit the detent to be released, the blast controlling valve then being opened by the steam pressure, means actuated by the other cam, whereby the rotation of the same shaft when the door is closed will cause the exhaust valve to open, and independent means for automatically closing said detent controlling valve and said exhaust valve when the cam which operates the particular valve has rotated out of operative position for maintaining the valve open. 7

1-. In a smoke preventer for a b iler furnace havingfire doors, a steam pipe, connections for supplying a blast of steam into the furnace, a rocker shaft, means whereby the opening of one of the fire doors will, cause the rocker shaft to rotate in one direction, means controlled by the closing of one of the doors to cause the shaft to rotate in the re verse direction, a valve which controls the admissi'onof steam to start the steam blast, a detent therefor, steam actuated means for releasing the detent, a valve which controls the admission of steam to release the detent, an exhaust pipe connected with the pipe which supplies steamto the furnace, a valve which controls the exhaust, two cams on said rocker shaft, means whereby one of the said cams actuatcs the opening of the valve which controls the inlet of steam to release said detent, and means whereby the other of said cams actuates the opening of the valve which controls the exhaust.

5, in a smoke preventer for a boiler furnace, having a fire door, a cylinder outside of the furnace, a steam pipe leading from the boiler to said cylinder, a steam pipe leading from said cylinder having connections for injecting ablast of steam into the furnace, a valve connected with said cylinder which controls the passage of steam from said cylinder to the pipe which leads to the injector, means for normally retaining said valve closed, a steam pipe which is adapted to supply steam from the boiler to release saiddetent mechanism on the said valve, a second valve which controls the admission of steam for actuating said releasing mechanism and which is normally closed when th fire door is closed, and means controlled by the opening of the fire door to open said last ientioned valve and thereby admit steam to release the detent mechanism from the first valve, whereby steam is admitted to the injector.

6. In a smoke preventer for a boiler furnace having a fire door, a steam pipe, and connections for injecting a blast of steam into the furnace, an exhaust pipe, a rocker shaft, means whereby the opening of a fire door will cause the shaft to rotate in one direction, means controlled by the closing of the fire door to cause said shaft to rotate in the reverse direction, a valve which controls the opening and closing of the blast into the furnace, a detent for normally holding said valve closed, steam actuated means for releasing said detent, a valve for controlling the admission of steam to release said detent, a cam on said rocker shaft, and means whereby when the rocker shaft is rotated by the opening of the fire door said cam will open the valve which controls the admission of steam to release said detent, whereby said steam injector controlling valve ispermitted to be opened by the steam pressure. p

7. In a smoke preventer for a boiler furnace having a'fire door, a steam pipe, and connections for injecting a blast of steam into the furnace, an exhaust pipe, a rocker shaft, means whereby the opening of a fire door will cause the shaft to rotate in one direction, means controlled by the closing of the fire door to cause said shaft to rotate in the reverse direction, a valve which controls the opening and closing of the blast into the furnace, a detent for normally holding said valve closed, steam actuated means for releasing said detent, a valve for controlling the admission of steam to release said detent, a cam on said rocker shaft, means whereby when'the rocker shaft is rotated by the opening of the fire door said cam will open the valve which controls the admission of steam to release said detent, whereby said steam injector controlling valve is permitted to be opened by the steam pressure, a second cam on said cam shaft, and means actuated by said second cam when the rocker shaft is rotated by the 010s ing of the door to open the exhaust, means controlled by said reverse rocking of the shaft to close the valve which controls the admission of steam to release the detent, and means which actuate the detent to then. close the valve which controls the admission of steam to the injector.

8. In a smoke preventer for a boiler furnace, having a firedoor, a steam pipe for discharging steam into the furnace, a valve for controlling the passage of steam through said pipe, a movable detent which is adapted to hold said valve closed, two cylinders each having a piston movable therein, a single piston rod carrying both of said pistons, a spring normally operative upon said detent to prevent the said valve from being opened, steam pipe connection between the boiler and one of said cylinders whereby the piston therein is adapted to be acted upon by steam pressure to move the piston rod and release the pressure on the detent, said other cylinder containing fluid and having a by-pass in the cylinder at opposite ends of the piston, the piston therein being formed with apertures through which the fluid will pass when the piston rod is moved in the direction which release the detent, a valve which controls the admission of steam to the first of said cylinders to move the piston rod in a direction to release said detent, a float valve within said second cylinder through which said piston rod passes, and which closes the apertures in said piston when the piston moves in the direction to release the detent, a valve which controls the exhaust from said cylinder, a supply pipe, and means for actuating said inlet and exhaust controlling valves to simultaneously open one and close the other.

9. In a smoke preventer for a boiler fur nace, having a fire door, a steam pipe and connections for discharging a blast of steam and air into the furnace, a valve for controlling the passage of steam into the furnace, a movable detent which is adapted to hold said valve closed, two cylinders each having a piston movable therein, a single piston rod carrying both of said pistons, a spring connected with said piston rod, and normally operative upon said detent to prevent the said valve from being opened, steam pipe connection between the boiler and one of said cylinders whereby the piston therein is adapted to be acted upon by the steam pressure to move said piston rod and release the pressure upon said detent, a valve which controls the admission of steam to move the piston to release the detent, means controlled by the opening of the fire door to open said last valve, said other cylinder be ing filled with fluid and having a by-pass into the cylinder at opposite ends of the piston in said cylinder, the piston therein being formed with apertures through which the fluid will pass when the, piston rod is moved in the direction which releases the detent, a float valve within said second cylinder through which said piston rod passes and. which closes the apertures in said piston with said piston rod and normally operative upon said detent to prevent the said valve from being opened, steam pipe connection between the boiler and one of said cylinders whereby the piston therein is adapted to be acted upon by the steam pres sure to move said piston rod and release the pressure on said detent, said other cylinder being filled with fluid and having a by pass from one end to the other and the piston therein being formed with valved apertures through which the fluid will pass when the piston rod is moved in the direction which releases the detent, a valve which controls the admission of steam to the first of said cylinders to move the said piston rod in a direction to release said detent, an exhaust pipe connected with the inlet pipe for the piston cylinder located between the piston cylinder and the inlet controlling valve, a second valve which controls the exhaust from said cylinder and supply pipe, and means for actuating both of said last mentioned valves so constructed and arranged that said valves are simultaneously actuated in a manner to close one of said valves coincidently with the opening of the other valve.

11. In a smoke preventer for a boiler furnace having a fire door, a steam pipe and connections for supplying a blast of steam and air into the furnace, a valve which con trols the passage of steam from said pipe to the furnace, two cylinders, steam supply pipes leading to said cylinders, a piston in each cylinder and a rod connecting both of said pistons whereby the two pistons move simultaneously, a detent connected with said rod which normally restrains said valve from being opened by steam pressure, steam pipe connection with one of said cylinders whereby steam is admitted to move said pistons and rod in a direction to release said detent, a valve which controls the admission of steam to said cylinder, means'whereby the opening of a furnace feed door will open said last mentioned valve and admit steam to release said detent and render the steam blast operative, an exhaust connected with the steam inlet pipe for the piston cylinder, located between the inlet controlling valve and the cylinder, a valve to open and close the exhaust, means controlled by theopening of the furnace door to close said exhaust valve, and means controlled by the closing of the furnace door to shut off the steam to the piston cylinder and open the exhaust,

means whereby the said piston rod and piston are given a reverse movement automatically after the steam to the piston cylinder is shut off and the said detent is again rendered operative, and means for causing the said return movement to occupy a predetermined period of time.

12. In a smoke preventer for a boiler furnace having afirc door, a steam pipe and nozzle connections for discharging a blast of steam and air into the furnace, a valve for controlling the passage of steam to said nozzles, a movable detent which is adapted to hold said valve closed, two cylinders each having a piston movable therein, a single piston rod carrying both of said pistons, a spring connected with said piston rod and normally operative upon said detent to pre vent the said valve from being opened, steam pipe connection between the boiler and one of said-cylinders whereby the piston therein is adapted to be acted upon by the steam pressure to move said piston rod and release the pressure on said detent, said other cylinder being filled with fluid and having a by pass to opposite ends of the piston, and the piston therein being formed with valved apertures through which the fluid will pass when the piston rod is moved in the direction which releases the detent, a check valve operative in connection with said apertured piston whereby on the return movement of the piston rod the fluid will be forced through the by pass to the other end of the piston, a valve which controls the admission of steam to the first of said cylinders to move the said piston rod in a direction to release said detent, a second valve which controls the exhaust from said cylinder and supply pipe, means for actuating both of said last mentioned valves so constructed and arranged that said valves are simultaneously actuated in a manner to close one of said valves coincidently with the opening of the other valve, mechanism connecting said actuating mechanism and the fire door or doors of the furnace whereby the opening of either one or more of the fire doors will immediately cause the closing of the exhaust and the opening of the inlet controlling valve, and means controlled by the closing of the said fire door or doors to open the exhaust and close the companion inlet controlling steam valve. v

In testimony whereof I afi ix my signature.

BRADFORD L. AMES. 

